Cut-off valve



(No Model.) n

B. WEBSTER.

GUT-OPF VALVE.

Patented Feb`.*20,1'883.

(No Model.)l 2 sheets-Sheena B. WEBSTER.

GUT-OPF VALVE.

Patented Feb.20,1883.

Darren @rares BENJAMIN WEBSTER, OF BRIDGEPOR'I', CONNECTICUT.

CUT-OFF VALVE.

PATENT @Finca SPECIFICATION forming part of Letters Patent No. 272,809, dated February 20, 1883.

l Application filed J une 19, 1882. (No model.)

To all whom it may concern:

Be it known that I, BENJAMIN VEBSTER, residing at Bridgeport, Fairleld county, lonnecticut, have invented certain Improvements in Gut-Oi'Valves forSteain-Engines, ot' which the following is a specification.

My invention is a valve device for steam engines, constructed as fully described hereinafter, to facilitate construction, redtice friction, and secure an automatic cut-oli, regulated, if' desired, from the governor.

In the drawings, Figure l is a transverse section through the cylinder and one of the valves of asteam-engine, showing my improvement. Fig. 2 is a longitudinal section, and Fig. 3 is a plan of Fig. 2.

Ais the cylinder, having the usual end ports, b b, which communicate each with a. hollow vertical valvefcasing, B, the two casings being in communication through ports tt d with the channel leading to the exhaust-port d. With the lower end ot' each casing B communicates a steam-pipe, Z.

IVithin each casing B is a hollow cylindricalV valve, D, open at the lower end and closed at the upper end, with the exception of one or more small apertures,f, by which a communication is formed with a chamber, fr, in the casing, above the valve, and from the upper end of the valve and through the bonnet or cap B extends a hollow shaft or sleeve, E, connected to an arm, T, by which the Valve is moved through the medium ofany suitable appliances.

In each valve D is a port, g, which, in the position shown at the left, Fig. 2, coincides with the cylinder port b, an external depression or channel, h, in the valve communicating with the port b, and with the exhaust-port d when the valve is in the position shown at the right, Fig. 2. Vhen the parts thus constructed are in the position shown in Fig. 2 the steam entering the lower end ofthe valve D at the left passes through the ports g b to the piston, while the exhaust-steam passes through the other port, b, channel h, port d, to the exhaustport d. The moving of each valve so as to reverse its position admits the steam to the right-hand end and puts the opposite end of the-cylinder iii connection with the exhaust. The steam, passing from the inside of each valve through the aperture f to the chamber x, enters a channel, t Fig. 2, in the casing outside of the valve F, and extends to a port, Fig. 1, below a spider, Gr, so as to maintain an equal pressure on both sides of the valve and balance the latter, so that the valve moves with but little friction.

As thus constructed, the parts may be used for engines in which the steam follows the pistou for its full stroke; but for engines in which the steam is used expansively l employ cut-oft' valves F, each secured to or cast with a stem, j, the lower end of which rests in a socket ot the spider G, while the upper end extends through the valve-sleeve E and carries an arm, H.

A shoulder, tu, on the spindle supports the valve D. This permits the valve to turn with but little friction. The valve F is a single block extending from the spindle to theiniier face of the valve D. These valves F are operated by any suitable appliances, so as to be held stationary until the valve D assumes the position shown at the left, Fig. 2, and until the steam is to be cut o", when by a quick movement the valve F is brought to the position shown in dotted lines, Fig. 2, thereby closing the port g and cutting olf the steam. Various appliances may be used forimparting these movements to the val ves. I will now describe' those which I have found to be effective.

A curved blade, c, upon the valve-stein is so constructed that the ow of the steain through the valve D toward the port g will tend to turn the valve to the position shown in dotted lines at the lelt, Fig. 2. The cut-oft'- valve arm H lies between ribs or shoulders m. m on the arm T of the main valve, these ribs being so arranged as to permit a limited movement of the arm Hindependently of the arm T.

In the arm H slides the shalt of a catch, N, capable of a limited longitudinal motion, thrown outward by a spring, o, and having a beveled end face, u.

Upon a bracket, M, secured in a stationary position upon the casing B, is a stop, P, having a beveled lace, u', land a straight face, n. The action ot' the steain on the blade v tends to brin g the straight face ol' the catch against the stop-face n. When the parts are in this IOO position the cut-off valve will be iu the position shown iufull lines at the left., Fig. 2. It, now, the stop P is carried outward in the direction of its arrow l, Fig. 3, the catch N will be released and the steam will turn the spindle j and bring the arm H rapidly against the shoulder m', carrying the valve F to the position shown in dotted lines, Fig. 2. As the arm T of the valve B moves in the opposite' direc- \tion theinclined face uct the catch N is brought against the inclined face u ot' the stop P and the catch N is forced back into the arm H until it leaves the stop, when the spring o will throw it outward to its'rst position.

When the cut-oli" is invariable the stop P may have a uniform motion eiected by a cam, K, on the shaft E operating on a slide, Q, car- .rying the stop P, which slide projects through a slot, t', in the bracket M and bears against a spring, s, which will permit the block and stop to move slightly when the catch is carried in the direction of the arrow 2, Fig. 3, or when the cam K bears on the block.

To secure a variable cutoff' I combine with the movable stop P appliances whereby its position is changed so as to carry it farther away from the catch as the governor is thrown out by the increased speed ot' the engine, thereby cutting oft' more quickly. Different devices may be employed for this purpose. I have shown a tapering key or wedge, R, bearing against a side of the bracket M and against a lip, t', of the block Q, so as to set the latter and the stop farther trom the catch as the key It is moved inward in the direction of its arrow as the speed of the governor increases.

This causes the cut-off valve to be sooner released, cutting oft' at a less stroke.

The cam K may swing upon the sleeve E,

and may be provided with an arm, K', and a screw, S', passing through a curved slot in the arm T, which will permit the cam to be set in any desired position.

fhile I have shown the valves F as provided with blades o, the latter may be dispensed with, andthe valves may be thrown by springs or otherwise.

I claiml. The combination, in a steam-engine, of a cylinder, A, hollow casings B, communicating with the end ports and with the exhaust, and hollow cylindrical valves D, arranged-in said casings, communicatingt with steam-inlet ports or pipes, and having portsg and external chan* nels, l1., substantially as set forth.

2. The combination ot' the cylinder, hollow cylindrical valves having ports g and channels h, and end ports,f, and casings B, having chambers a: and channels y, for the purpose speci-V tied.

3. The combination, with the cylindtical valves D, having ports g and channels h, of cut-off' valves F, arranged within the valves D, adapted to closethe ports g, and appliances whereby the valves D and Finay be operated independently but relatively, substantially as set forth.

4. The combination, with the valveD, of the inside cut-oft' valve, F, constructed and provided with a curved blade, t1, substantially as and for the p urpose specified.

5. Tile combination ot' the valve D, provided with a rock-arm, T, the valve F, provided with a rock-arm, H, carrying a catch, N, a stop, P, and appliances, substantially as described, for moving the stop away from the catch, for the purpose specilied.

6. The combination, with the stop P and devices for moving the same after its contact with the catch, of' appliances adapted to be connected to and operated by the governor for automatically controlling the position of the stop P, substantially as set forth.

ln testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

BENJAMIN WEBSTER.

Witnesses:

SMIL. T. HoUcrHToN,

W. H. SILLIMAN. 

